Aspects of this disclosure relate generally to telecommunications, and more particularly to techniques for joint transmission in unlicensed spectrum.
Long Term Evolution networks are expanding operation in unlicensed radio frequency (RF) bands for data offload. For example, using carrier aggregation features, LTE networks can operate at higher data rates while using both licensed and unlicensed RF bands. A wireless communication network may be deployed to provide various types of services (e.g., voice, data, multimedia services, etc.) to users within a coverage area of the network. In some implementations, one or more access points (e.g., corresponding to different cells) provide wireless connectivity for access terminals (e.g., cell phones) that are operating within the coverage of the access point(s). In some implementations, peer devices provide wireless connectively for communicating with one another.
Moreover, as LTE networks expand operation in unlicensed RF bands in order to focus on higher capacity and provide higher bitrates, a number of other requirements need to be fulfilled. For example, the LTE networks need to provide increased peak data rates, higher spectral efficiency, increased number of simultaneously active subscribers, and improved performance at cell edges. In order to improve performance at cell edges, Coordinated Multi-Point operation (CoMP) was introduced. In CoMP, a number of transmit points provide coordinated transmission in the downlink, and a number of receive points provide coordinated reception in the uplink. In the case of downlink, data is available for transmission from two transmitting network entities or transmit points (e.g., two access points or base stations, also referred to as cells or nodes). When two or more network entities transmit on the same frequency and in the same subframe the transmission may be referred to as a “joint transmission.” A joint transmission can be broadly described as a simultaneous or concurrent transmission of data to a user equipment or UE (also referred to as a wireless device, wireless terminal device, wireless terminal, or mobile device) from multiple cooperating access points.
Similarly, multicast-broadcast single-frequency network (MBSFN) was introduced to further improve the efficiency of the enhanced Multimedia Broadcast Multicast Service (eMBMS) service, which can deliver services such as mobile TV using the LTE infrastructure. A network device may transmit the same data (identical data) to multiple UEs simultaneously. Furthermore, network devices configured in MBSFN mode may also engage in joint transmission on the downlink. For example, multiple network entities may transmit the identical data simultaneously so that device UE may receive the same data from multiple access points.
As such, and given the growing use of the unlicensed spectrum, techniques are needed to provide efficient and improved identification of the type of downlink transmissions from one or more network entities.